Commit Graph

23 Commits

Author SHA1 Message Date
Jan Kara a898cb621a quota: Detect loops in quota tree
Syzbot has found that when it creates corrupted quota files where the
quota tree contains a loop, we will deadlock when tryling to insert a
dquot. Add loop detection into functions traversing the quota tree.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-12 14:14:49 +01:00
Jan Kara a1e1b2beca quota: Drop GFP_NOFS instances under dquot->dq_lock and dqio_sem
Quota code acquires dquot->dq_lock whenever reading / writing dquot.
When reading / writing quota info we hold dqio_sem.  Since these locks
can be acquired during inode reclaim (through dquot_drop() -> dqput() ->
dquot_release()) we are setting nofs allocation context whenever
acquiring these locks. Hence there's no need to use GFP_NOFS allocations
in quota code doing IO. Just switch it to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:11 +01:00
Zhihao Cheng 191249f708 quota: Add more checking after reading from quota file
It would be better to do more sanity checking (eg. dqdh_entries,
block no.) for the content read from quota file, which can prevent
corrupting the quota file.

Link: https://lore.kernel.org/r/20220923134555.2623931-4-chengzhihao1@huawei.com
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-09-29 15:37:30 +02:00
Zhihao Cheng 3fc61e0e96 quota: Replace all block number checking with helper function
Cleanup all block checking places, replace them with helper function
do_check_range().

Link: https://lore.kernel.org/r/20220923134555.2623931-3-chengzhihao1@huawei.com
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-09-29 15:37:28 +02:00
Zhihao Cheng 6c8ea8b8cd quota: Check next/prev free block number after reading from quota file
Following process:
 Init: v2_read_file_info: <3> dqi_free_blk 0 dqi_free_entry 5 dqi_blks 6

 Step 1. chown bin f_a -> dquot_acquire -> v2_write_dquot:
  qtree_write_dquot
   do_insert_tree
    find_free_dqentry
     get_free_dqblk
      write_blk(info->dqi_blocks) // info->dqi_blocks = 6, failure. The
	   content in physical block (corresponding to blk 6) is random.

 Step 2. chown root f_a -> dquot_transfer -> dqput_all -> dqput ->
         ext4_release_dquot -> v2_release_dquot -> qtree_delete_dquot:
  dquot_release
   remove_tree
    free_dqentry
     put_free_dqblk(6)
      info->dqi_free_blk = blk    // info->dqi_free_blk = 6

 Step 3. drop cache (buffer head for block 6 is released)

 Step 4. chown bin f_b -> dquot_acquire -> commit_dqblk -> v2_write_dquot:
  qtree_write_dquot
   do_insert_tree
    find_free_dqentry
     get_free_dqblk
      dh = (struct qt_disk_dqdbheader *)buf
      blk = info->dqi_free_blk     // 6
      ret = read_blk(info, blk, buf)  // The content of buf is random
      info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free)  // random blk

 Step 5. chown bin f_c -> notify_change -> ext4_setattr -> dquot_transfer:
  dquot = dqget -> acquire_dquot -> ext4_acquire_dquot -> dquot_acquire ->
          commit_dqblk -> v2_write_dquot -> dq_insert_tree:
   do_insert_tree
    find_free_dqentry
     get_free_dqblk
      blk = info->dqi_free_blk    // If blk < 0 and blk is not an error
				     code, it will be returned as dquot

  transfer_to[USRQUOTA] = dquot  // A random negative value
  __dquot_transfer(transfer_to)
   dquot_add_inodes(transfer_to[cnt])
    spin_lock(&dquot->dq_dqb_lock)  // page fault

, which will lead to kernel page fault:
 Quota error (device sda): qtree_write_dquot: Error -8000 occurred
 while creating quota
 BUG: unable to handle page fault for address: ffffffffffffe120
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 Oops: 0002 [#1] PREEMPT SMP
 CPU: 0 PID: 5974 Comm: chown Not tainted 6.0.0-rc1-00004
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
 RIP: 0010:_raw_spin_lock+0x3a/0x90
 Call Trace:
  dquot_add_inodes+0x28/0x270
  __dquot_transfer+0x377/0x840
  dquot_transfer+0xde/0x540
  ext4_setattr+0x405/0x14d0
  notify_change+0x68e/0x9f0
  chown_common+0x300/0x430
  __x64_sys_fchownat+0x29/0x40

In order to avoid accessing invalid quota memory address, this patch adds
block number checking of next/prev free block read from quota file.

Fetch a reproducer in [Link].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216372
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
CC: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220923134555.2623931-2-chengzhihao1@huawei.com
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-09-29 15:37:25 +02:00
Zhang Yi d0e36a62bd quota: correct error number in free_dqentry()
Fix the error path in free_dqentry(), pass out the error number if the
block to free is not correct.

Fixes: 1ccd14b9c2 ("quota: Split off quota tree handling into a separate file")
Link: https://lore.kernel.org/r/20211008093821.1001186-3-yi.zhang@huawei.com
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2021-10-11 10:57:04 +02:00
Zhang Yi 9bf3d20331 quota: check block number when reading the block in quota file
The block number in the quota tree on disk should be smaller than the
v2_disk_dqinfo.dqi_blocks. If the quota file was corrupted, we may be
allocating an 'allocated' block and that would lead to a loop in a tree,
which will probably trigger oops later. This patch adds a check for the
block number in the quota tree to prevent such potential issue.

Link: https://lore.kernel.org/r/20211008093821.1001186-2-yi.zhang@huawei.com
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2021-10-11 10:55:47 +02:00
Zhen Lei ce1b06c5f5 quota: remove unnecessary oom message
Fixes scripts/checkpatch.pl warning:
WARNING: Possible unnecessary 'out of memory' message

Remove it can help us save a bit of memory. After that, the static
function getdqbuf() becomes unnecessary, get rid of it and instead call
kmalloc() directly.

Link: https://lore.kernel.org/r/20210618014720.1977-2-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-06-22 10:40:52 +02:00
Jan Kara 10f04d40a9 quota: Don't overflow quota file offsets
The on-disk quota format supports quota files with upto 2^32 blocks. Be
careful when computing quota file offsets in the quota files from block
numbers as they can overflow 32-bit types. Since quota files larger than
4GB would require ~26 millions of quota users, this is mostly a
theoretical concern now but better be careful, fuzzers would find the
problem sooner or later anyway...

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-11-03 11:17:00 +01:00
Thomas Gleixner 09c434b8a0 treewide: Add SPDX license identifier for more missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have MODULE_LICENCE("GPL*") inside which was used in the initial
   scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Jan Kara 7b9ca4c61b quota: Reduce contention on dq_data_lock
dq_data_lock is currently used to protect all modifications of quota
accounting information, consistency of quota accounting on the inode,
and dquot pointers from inode. As a result contention on the lock can be
pretty heavy.

Reduce the contention on the lock by protecting quota accounting
information by a new dquot->dq_dqb_lock and consistency of quota
accounting with inode usage by inode->i_lock.

This change reduces time to create 500000 files on ext4 on ramdisk by 50
different processes in separate directories by 6% when user quota is
turned on. When those 50 processes belong to 50 different users, the
improvement is about 9%.

Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17 22:07:59 +02:00
Jan Kara bc8230ee8e quota: Convert dqio_mutex to rwsem
Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes
yet.

Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17 18:52:48 +02:00
Jan Kara 0066373d9f quota_v2: Implement get_next_id() for V2 quota format
Implement functions to get id of next existing quota structure in quota
file for quota tree based formats and thus for V2 quota format.

Signed-off-by: Jan Kara <jack@suse.cz>
2016-02-09 13:05:23 +01:00
Konstantin Khlebnikov 69a25ee217 quota: paranoia: check quota tree root
Root level in quota tree must be already allocated otherwise this block
could be used for something else.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
2015-03-04 16:42:45 +01:00
Eric W. Biederman 4c376dcae8 userns: Convert struct dquot dq_id to be a struct kqid
Change struct dquot dq_id to a struct kqid and remove the now
unecessary dq_type.

Make minimal changes to dquot, quota_tree, quota_v1, quota_v2, ext3,
ext4, and ocfs2 to deal with the change in quota structures and
signatures.  The ocfs2 changes are larger than most because of the
extensive tracing throughout the ocfs2 quota code that prints out
dq_id.

quota_tree.c:get_index is modified to take a struct kqid instead of a
qid_t because all of it's callers pass in dquot->dq_id and it allows
me to introduce only a single conversion.

The rest of the changes are either just replacing dq_type with dq_id.type,
adding conversions to deal with the change in type and occassionally
adding qid_eq to allow quota id comparisons in a user namespace safe way.

Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:41 -07:00
Joe Perches 055adcbd7d quota: Use %pV and __attribute__((format (printf in __quota_error and fix fallout
Use %pV in __quota_error so a single printk can not be
interleaved with other logging messages.
Add __attribute__((format (printf, 3, 4))) so format
and arguments can be verified by compiler.
Make sure printk formats and arguments match.

Block # needed a pointer dereference.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2011-01-10 19:04:05 +01:00
Jiaying Zhang fb5ffb0e16 quota: Change quota error message to print out disk and function name
The current quota error message doesn't always print the disk name, so
it is hard to identify the "bad" disk when quota error happens.

This patch changes the standardized quota error message to print out disk name
and function name. It also uses a combination of cpp macro and inline function
to provide better type checking and to lower the text size of the message.

[Jan Kara: Export __quota_error]

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2010-07-21 16:05:58 +02:00
Jiaying Zhang 1907131bbe dquot: Detect partial write error to quota file in write_blk() and add printk_ratelimit for quota error messages
This patch changes quota_tree.c:write_blk() to detect error caused by partial
write to quota file and add a macro to limit control printed quota error
messages so we won't fill up dmesg with a corrupted quota file.

Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2010-05-21 19:30:49 +02:00
Dmitry Monakhov dde9588853 quota: Make quota stat accounting lockless.
Quota stats is mostly writable data structure. Let's alloc percpu
bucket for each value.

NOTE: dqstats_read() function is racy against dqstats_{inc,dec}
and may return inconsistent value. But this is ok since absolute
accuracy is not required.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2010-05-21 19:30:41 +02:00
Jan Kara 268157ba67 quota: Coding style fixes
Wrap long lines, remove assignments from conditions, rewrite two
overcomplicated for loops.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-03-26 02:18:38 +01:00
Jan Kara 7a2435d874 quota: Remove superfluous inlines
Remove inlines of large functions to decrease code size (saved 1543
bytes).

Signed-off-by: Jan Kara <jack@suse.cz>
2009-03-26 02:18:37 +01:00
Jan Kara d26ac1a812 quota: Remove dqbuf_t and other cleanups
Remove bogus typedef which is just a definition of char *.
Remove unnecessary type casts.
Substitute freedqbuf() with kfree.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-03-26 02:18:35 +01:00
Jan Kara 884d179dff quota: Move quota files into separate directory
Quota subsystem has more and more files. It's time to create a dir for it.

Signed-off-by: Jan Kara <jack@suse.cz>
2009-03-26 02:18:35 +01:00